A woman's body undergoes a variety of changes to prepare for the growth, nourishment, and birth of a child.
An early sign of pregnancy is the cessation of menses, which occurs due to the rising levels of human chorionic gonadotropin (HCG), a hormone produced by the placenta. This trimester is characterized by various discomforts, including nausea and vomiting, (so called morning sickness), increased frequency of urination due to pressure of the enlarging uterus on the bladder, and breast soreness or tingling due to hormonal stimulation.
Increasing abdominal girth and pressure from the growing uterus can lead to constipation. Normal intermittent uterine contractions, called Braxton-Hicks contractions, may occur. The mother may experience lightheadedness and may even faint due to the effects of the hormones on the blood vessels and the amount of blood diverted to the uterus, placenta, and fetus. Heartburn becomes an increasing problem because of the increasing pressure on the stomach by the enlarging uterus and delayed emptying of the stomach.
The last weeks of pregnancy become increasingly uncomfortable. Headaches, hemorrhoids, varicose vein, and swelling of the legs may occur. Shortness of breath is common due to the enlarged uterus, which prevents full expansion of the lungs. In the last days of gestation increased pelvic discomfort develops, caused by the dropping of the fetal head into the pelvis. False labor pains, or contractions of the uterus that do not lead to progressive dilatation, or opening, of the cervix, often occur.
Women who receive prenatal care have fewer complications of pregnancy and birth and have healthier babies. Also the earlier and more consistently the care is received, the better the outcome. Education about pregnancy and child rearing is an important part of prenatal care, as are detection and treatment of risk to the mother and fetus are inherent in the provision of prenatal care. In fact, the best time to assess many of these risks is before a woman conceives. Therefore, it is becoming popular for women to receive preconception care while still planning a pregnancy.